If you or someone close to you is wearing glasses, then you’ve probably heard the term bifocal before. But unless you are wearing bifocal lenses yourself, it is possible that you don’t know exactly what the term means. So whether you are curious to find out what a bifocal lens is and what it is used for, or you already know some general information about bifocals, but want to dig deeper into the subject, make sure to read on. We will be providing you with everything you need to know about bifocal lenses.
What Is a Bifocal?
A bifocal lens is a lens created with two different optical powers divided by a horizontal line across the lens. The part that sits above is designed for seeing at a distance, while the one that sits below is used for looking at objects that are close to you. So, the same lens has two prescriptions. Even if this sounds like good news because you won’t be forced to change between more pairs of glasses, the fact that the optical powers vary according to the distance at which you are perceiving an object, this can give you an uncomfortable feeling of distortion, or the impression of a narrow field of vision. But this is something that you can get accustomed to with time.
What Are Bifocals Used for?
A bifocal lens is usually prescribed to people who deal with presbyopia, the rather common vision issue that people between the ages of 40 and 45 deal with. This condition causes you to have difficulties when focusing on small text, even if it is right in front of you. And this is where the bifocal lenses come in, to help you tackle that issue.
Bifocals vs Other Types of Lenses
A lot of people have difficulties understanding the differences between bifocals and other types of lenses such as trifocals or progressives (also called no-line bifocals). This is why we have decided to include a short summary of the differences between these types of lenses.
Bifocals vs Trifocals
As the name already suggests, the main difference between bifocals and trifocals is the fact that while bifocals have two different prescriptions, one for objects that are far away and one for objects that are near, trifocals store 3 prescriptions in the same lens. One is for objects that are far from the wearer, one for intermediate distance (which is approximatively at arm’s length), and one for near vision. Another difference would be that trifocals are usually prescribed to people who have a more advanced case of presbyopia.
Bifocals vs Progressive (Multifocal, No-line)
Again, the name is suggestive once more in realizing the difference between bifocals and progressives. While bifocals have a clearly delimited line between the two prescriptions, multifocals, no-line, or progressive, whatever you want to call them, have a more gradual transition between the two. The progressive ones, due to the higher range of vision, have multiple vision distances, not only two, as in the case of bifocals.
Types of Bifocal Lenses
In case you want to give bifocal lenses a try, but the many options out there confuse you, take a look at the most common types of bifocal lenses and what are their characteristics:
- Aspheric Designs: This design places both prescriptions near the center of the eye, to help it ignore objects that are far away when focusing on something near, and ignore objects that are close when you want to focus on something far away. It might take some time to get used to this design, as your visual system has to select the prescription according to whether you are trying to look at an object close to you or at one that is far away.
- Concentric Designs: In this type of design, the prescriptions are positioned in a bull’s-eye manner, with either the near one or the distance one placed at the center. This arrangement depends on each patient’s lifestyle: if you are more likely to look at objects that are close to you during the day, then the near one would be in the middle, but if your daily activities entail looking at objects that are far away, then the distance one would be positioned at the center. This positioning also depends on your pupil size. If your pupils are larger, near vision would be placed at the center, if you have small pupils, the far vision would occupy that place. If you need an extra prescription for intermediate vision, another ring can be placed between the two, but this would turn the lens into a multifocal one.
- Translating Designs: The far and near prescriptions are clearly separated, and your eye moves between the two according to the needs of the moment. Usually, the distance prescription is the one on top, and the near one on the bottom, but this can be adjusted according to your lifestyle as well.
It is also important to know that all of these bifocal lens designs come in two different options:
- Gas Permeable Lenses: They are made of a type of plastic that transmits oxygen, and they are extremely resistant against bacteria.
- Soft Lenses: They are made from water mixed with plastic that turns into a gel. They are less resistant than the gas permeable ones, often only lasting one day, and they are more susceptible to bacteria as well.
Is a Bifocal Lens the Right Choice for You?
Of course, the only people who can determine if a bifocal lens is the right choice for you are you and your physician. But we would like to help you decide by providing you with some of the benefits and the drawbacks of wearing a bifocal lens.
- You won’t need special reading glasses.
- You will be able to see perfectly both far away and near.
- They don’t require that many adjustments.
- It takes some time before you learn how to switch focus between prescriptions.
- Depth perception can sometimes be affected by bifocal lenses.
- They can sometimes strain your eyes, especially if you have your reading prescription in the lower lens and you do a lot of work that involves looking at objects closely.
Bifocal Contact Lens Brands and Prices
One of the first things people who are contemplating wearing contact lenses ask themselves is how expensive they are. We thought about that aspect too. That is why we decided to do some research and look at some of the most popular brands of bifocal contact lenses and their price:
- Air Optix is one of the most popular brands for both bifocal and multifocal lenses, and the average price of a box of 6 lenses is $54.
- Proclear is another popular brand that sells a box of 6 lenses with $46.
- Biofinity also sells a box of 6 lenses with $46.
- Acuvue: Finally, Acuvue offers a pack of 90 1-day contact lenses for only $69.
Bifocal Contact Lens Alternatives
If a bifocal contact lens doesn’t sound like something you would like, there are plenty of alternatives out there. You can get reading glasses and only wear normal, distance contact lenses. The drawback here is that you will have to constantly take care that you have your glasses with you. The multifocal contact lenses are another popular option. This seems like a better option if you need more than two prescriptions and you want to be able to gradually switch between them, instead of having a harsher transition, as is the case with bifocal lenses.
Finally, another popular alternative are the monovision contact lenses. But how do these work? Well, you will have a lens on one eye for your far vision, and another in the second eye for your near vision. What happens is that when you look at an object far away, the eye that has the near lens will get blurred, and when you look at something near, the other eye will get blurred. However, the results seem to be clear and the lenses comfortable, and people are adapting to it rather quickly, not even realizing which eye is supposed to be the distance one or the near one.
Summing Everything Up
To conclude this short guide to bifocal lenses, we would like to point out that even if new technology such as multifocal lenses or monovision have gained popularity recently, bifocals still remain one of the most used types of lenses. Of course, the choice depends a lot on some of the characteristics that your eyes have and that only your doctor can notice and inform you about. It also depends a lot on the type of lens you feel more comfortable with. And bear in mind that until you find said lens, you might have to try several options.
Your lifestyle choices also impact the type of lens that suits you best, depending on whether you work a lot on the computer or with books, or you are a more adventurous type of person that works outdoors. The whole process may sound really complicated, but do not worry, you will eventually find the lens that best suits you. And we hope our guide has at least provided you with a useful background before you take a trip to the doctor and decide on what lens to wear from now on.